set-up-git.md: clarify URL in git clone command

Fixes https://github.com/moby/moby/issues/47407

Signed-off-by: Erik Sjölund <erik.sjolund@gmail.com>

docs/contributing/set-up-git.md

@@ -66,9 +66,10 @@ target="_blank">moby/moby repository</a>.
 8. Clone the fork to your local host into a repository called `moby-fork`.
 
    ```bash
-   $ git clone https://github.com/moxiegirl/moby.git moby-fork
+   $ git clone https://github.com/YOUR_ACCOUNT/moby.git moby-fork
    ```
 
+    In the command above replace `YOUR_ACCOUNT` with your GitHub username.
     Naming your local repo `moby-fork` should help make these instructions
     easier to follow; experienced coders don't typically change the name.